Background: Medicinal plants are the most important source for life saving drugs for majority of the world's population. Iran, with more than 7500 existing plant species, is one of the main regions of biodiversity and a natural habitat for more than 900 species with medicinal properties. Ribes khorassanicum (Grossulariaceae) is such a plant with the height of 1.5-2.5m and endemic to Khorasan. It is an element of Irano-Touranian region distributed in Hezar-Masjed Chain Mountains with the altitude of 2400-2700 m.a.s.l.. Flowering is in the second half of spring and fruit ripening is in the middle of summer. Objective: During field work, we found that local people consume the dried fruits treat blood pressure, cardiac problems and digestion poisoning. Since no study was performed previously, we decided to have an investigation on Phytochemicals and antibacterial effects of the plant. Method: Alcoholic extract of the flowers, unripe and ripe fruits were done in the lab. Some pharmaceutical materials were recognised and evaluated in different organs. Effects of alcoholic extract with concentrations of 6.25%, 12.5%, 25%, 50% and 75% on certain intestinal bacteria viz. Salmonella spp., Shigella flexneri, Escherichia coli, Proteus mirabilis, Staphylococus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae were studied. Results: The results showed existence of some pharmaceutical materials such as Alkaloids (A), Flavonoids (F), Saponins (S), and Tanans. The grade of F, S and T were +2, -, +4 in flowers, +4, +1, +1 in unripe fruits and +1, - and +- in ripe fruits, respectively. The concentration of Alkaloid in flowers, unripe and ripe fruits was 5, 38 and 22 mg/lit, respectively. This study revealed that ripe fruit extract has an inhibitory effect on growth of bacteria mentioned above. The extent of the inhibition was related to the concentration of the extract. Conclusion: Existence of high amounts of Alkaloids, Flavonoids and Tanans along with antibacterial effects revealed the medicinal properties of the plant.